On Fri, 2014-01-17 at 09:13 -0500, Vivek Goyal wrote: > On Fri, Jan 17, 2014 at 04:59:13PM +1100, Benjamin Herrenschmidt wrote: > > On Thu, 2014-01-16 at 20:52 -0800, Eric W. Biederman wrote: > > > > > > I think we have largely survied until now because kdump is so popular > > > and kdump winds up having to reinitialize devices from any random > > > state. > > > > kdump also doesn't care too much if the device is still DMA'ing to the > > old kernel memory :-) > > In principle kdump does not care about ongoing DMAs but in practice it > is giving us some headaches with IOMMU. Various kind of issues crop up > during IOMMU intialization in second kernel while DMA is ongoing and > unfortunately no good solution has made into upstream yet. > > Well, ongoing DMA and IOMMU seems to be orthogonal to using ->remove() > in kexec. So I will stop here. :-) Right, it's an orthogonal problem. I think hot resetting the bus might solve it too though. It's even worse on ppc because the resulting iommu errors trigger those "EEH freeze" that we have here blocking the devices out etc... Ben. > Thanks > Vivek > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
